theminiking Posted August 27, 2012 Share Posted August 27, 2012 Hi guys, didn't think I'd be calling on your help so soon! Only had the car a week and now have a CEL for a multiple cylinder missfire. It's had a bit of a lumpy idle all week and yesterday decided to start cutting out at traffic lights and this morning won't idle at all. Car is a 54 plate UK spec with Vortech supercharger, Nismo exhaust, Kintex cats, Kinetix Plenum, RC550 injectors, Uprev MAF sensor, and remap. Also has a Zeitronix ZT2 wideband AFR which is showing a very lean engine (16 to 17 cruising at motorway speeds), especially at idle when it goes off the scale at AFR 21+ which is a bit concerning. Does anyone have any ideas what could be causing this extreme leaning? I suspect it's either an air leak after the MAF or a faulty MAF or injector (both only fitted 2 months ago) but I'm just a bit surprised it hasn't thrown up a fault code running so lean? Laurie. Quote Link to comment Share on other sites More sharing options...
theminiking Posted August 27, 2012 Author Share Posted August 27, 2012 Oops, sorry, posted in the wrong section. Could someone please move to 350z tech section. Cheers! Quote Link to comment Share on other sites More sharing options...
Beavis Posted August 27, 2012 Share Posted August 27, 2012 Oops, sorry, posted in the wrong section. Could someone please move to 350z tech section. Cheers! Done. Quote Link to comment Share on other sites More sharing options...
Ekona Posted August 27, 2012 Share Posted August 27, 2012 Definitely sounds like a massive air leak to me. Check all the hoses, gaskets etc. Don't be too concerned about those AFR readings, under light cruise and at idle those numbers are fine. It's under WOT and boost you want to be seeing 12s really. Quote Link to comment Share on other sites More sharing options...
ZMANALEX Posted August 27, 2012 Share Posted August 27, 2012 Possibly hose off, or split some where. Should be easy to trace. Best not to drive until sorted for fear of det. Alex Quote Link to comment Share on other sites More sharing options...
theminiking Posted August 27, 2012 Author Share Posted August 27, 2012 Definitely sounds like a massive air leak to me. Check all the hoses, gaskets etc. Don't be too concerned about those AFR readings, under light cruise and at idle those numbers are fine. It's under WOT and boost you want to be seeing 12s really. From what I've read idle AFR should be closer to 14ish, I know it's not dangerous when it's not being driven hard but definitely isn't right! Air leak sounds about right, guess I have an excuse to get to know the 350s engine now then! I did notice one of the intercooler to MAF pipe joints has an extra layer of silicone hose sleeved over the top of it, could be something nasty lurking under there I guess? Quote Link to comment Share on other sites More sharing options...
Ekona Posted August 27, 2012 Share Posted August 27, 2012 14.7 is stoich, no need to run that rich under idle as there's no load on the engine. Quote Link to comment Share on other sites More sharing options...
theminiking Posted August 29, 2012 Author Share Posted August 29, 2012 Sussed it! One of the bolts holding down the Kinetix plenum had come loose and the gasket had blown out. Does anyone know of anywhere that deals in Kinetix spares? I've read that they won't provide a new gasket as it's bonded to the plenum and they want you to return it to the states to get it replaced?! If not I'll probably be getting some cork gasket and making one. Quote Link to comment Share on other sites More sharing options...
ZMANALEX Posted August 29, 2012 Share Posted August 29, 2012 If it is the gasket that fits to the top of the inlet manifold which hooks up to the plenum then I have them in stock and good to go same/next day Alex. Quote Link to comment Share on other sites More sharing options...
theminiking Posted August 29, 2012 Author Share Posted August 29, 2012 If it is the gasket that fits to the top of the inlet manifold which hooks up to the plenum then I have them in stock and good to go same/next day Alex. I'm beginning to see why you have your own smiley! You have PM! Quote Link to comment Share on other sites More sharing options...
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